Skeletal muscles express multiple nuclear receptors. However, their role in muscular dystrophy is unknown. Recently, we found that transgenic mice over-expressing nuclear receptor PPAR-delta in skeletal muscles ran twice as long and as far as non-transgenic mice on a treadmill [Transgenic/non-transgenic; time: 140 min/80 min; distance: 1800 m/800 m]. Such an improvement in skeletal muscle performance on activating PPAR-delta may be beneficial in dystrophic muscles, which are characterized by weakness and fatigue. In this proposal we will test the hypothesis that activation of PPAR-delta decreases the pathology of Duchenne muscular dystrophy (DMD). All the experiments related to the hypothesis will be performed in mdx mice, a rodent model of DMD. In brief, we will measure the suppressive effect of both PPAR-delta agonist (GW1516) treatment and muscle specific PPAR-delta over-expression on the pathological biomarkers of DMD in mdx mice at the level of muscle morphology, gene expression and contractile properties. The results from our study will reveal whether PPAR-delta is an appropriate target to counteract DMD as well as whether an orally active PPAR-delta agonist can decrease the pathology of DMD. [unreadable] [unreadable] [unreadable]